Time Warner yesterday officially named ex-Meredith executive Jack Griffin as CEO of its Time Inc. division, the nation’s largest magazine publisher, whose titles include Time, People, Sports Illustrated and InStyle.

The 50-year-old Griffin resigned on Aug. 2 from Meredith, where he was president and CEO of the National Media Group, which includes Better Homes & Gardens and Ladies’ Home Journal. Nypost.com broke the news that he was heading to Time Inc. on Aug. 4.

Meredith Corp., the Des Moines-based media company that also includes TV stations, tried to entice Griffin to stay by offering to promote him to president under CEO Stephen Lacy. Griffin did not want to relocate to Des Moines for a second time in his career and turned down the offer, sources said.

In his first order of business yesterday, Griffin dined with his predecessor, Ann Moore, in the Time Inc. corporate cafeteria. Moore’s contract expires in 2011, but she will exit at the end of this year after serving as chairman during a transition period.

At Meredith, Griffin gained critical mass with the acquisition of Gruner & Jahr titles such as Family Circle and Fitness, and posted ad page gains at the height of the Great Recession.

He also pushed Meredith’s integrated marketing programs and acquired the mobile hot shop The Hyperfactory earlier this year. Big advertisers such as Kraft, L’Oreal and Coca-Cola can turn to the publisher for turnkey marketing that goes far beyond selling ad pages in magazines and on Web sites.

“I think Jack’s tenure will be transformative rather than evolutionary at Time Inc.,” said industry consultant Peter Kreisky. “He’s a total re-inventor. He’s quiet but profound.”

“He’s redesigned the business model for the industry that everyone is going to follow,” Kreisky said. “He understands how the impact of digital is pervasive in every element of the magazine industry.”

Adds Griffin: “When I talk about integrated marketing, it’s not only an opportunity, but an imperative.”

Some observers also speculated that Griffin might trim Time Inc.’s portfolio of more than 100 magazines.

“I don’t know where that came from,” said Griffin, adding he has no mandates. “But it makes sense that you want to put resources where you have viable opportunities. All publishing companies are going through it.”